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Biomedical subjects

H A van Diemen

Publications and source records attributed to H A van Diemen.

8 recordsLinked to original sources
PubMed1994

4-Aminopyridine is superior to 3,4-diaminopyridine in the treatment of patients with multiple sclerosis.

OBJECTIVE: To compare the efficacy and toxicity of 4-aminopyridine and 3,4-diaminopyridine in patients with multiple sclerosis. DESIGN: Intervention study with a before-after design and a randomized, double-blind, crossover design. SETTING: University referral center. PATIENTS: Twenty-four patients with definite multiple sclerosis who had been treated in a previous clinical trial with 4-aminopyridine. INTERVENTIONS: Nonresponders to treatment with 4-aminopyridine (14 patients) were treated with 3,4-diaminopyridine in a 4-week, open-label trial with doses up to 1.0 mg/kg of body weight (before-after design). Responders to treatment with 4-aminopyridine (10 patients) participated in a comparative study of 6 weeks' duration with 4-aminopyridine and 3,4-diaminopyridine according to a randomized, double-blind, double-crossover design. MAIN OUTCOME MEASURES: Neurophysiologic variables for nonresponders, neurologic functions and symptoms on a visual analogue scale for responders, and side effects for both groups. RESULTS: Toxicity profiles of 4-aminopyridine and 3,4-diaminopyridine were different, and systemic tolerability was reduced for 3,4-diaminopyridine. 4-Aminopyridine was more effective than 3,4-diaminopyridine, especially for ambulation, fatigue, and overall daily functioning. CONCLUSION: Our data suggest that, concerning both efficacy and side effects, 4-aminopyridine is superior to 3,4-diaminopyridine in the treatment of patients with multiple sclerosis.

4-Aminopyridine↗
PubMed1993

4-Aminopyridine induces functional improvement in multiple sclerosis patients: a neurophysiological study.

This study reports on the neurophysiological measurements that were performed in the context of a randomized, double-blind, placebo-controlled, cross-over study with intravenously administered 4-aminopyridine (4-AP) in 70 patients with definite multiple sclerosis (MS). A beneficial effect of 4-AP was found for both visual evoked response and eye movement registration parameters. This study extends the experimental data obtained on animal nerve fibers, showing that 4-AP can improve impulse conduction in demyelinated nerve, to clinical data which indicate that 4-AP induces an objective improvement in the central nervous system function in MS-patients. It thereby also provides a theoretical basis for clinical efficacy of 4-AP in MS.

4-Aminopyridine↗
PubMed1992

Determination of 4-aminopyridine in serum by solid-phase extraction and high-performance liquid chromatography.

An assay for the determination of 4-aminopyridine in serum has been developed using 3,4-diaminopyridine as internal standard and reversed-phase high-performance liquid chromatography with detection at 244 nm. A mobile phase of acetonitrile-methanol-ethanol-1% ammonium carbonate (75:10:10:5) provided excellent separation of both compounds. Samples were extracted on solid-phase columns. The linearity, precision, recovery and the limit of detection were all sufficient for the routine use of this assay in clinical studies of patients treated with 4-aminopyridine.

4-Aminopyridine↗
PubMed1992

A pilot study on the influence of a corticotropin (4-9) analogue on Vinca alkaloid-induced neuropathy.

In a randomized, double-blind, placebo-controlled pilot study, we examined the effect of Org 2766--a corticotropin (4-9) analogue--on neurotoxicity in 28 patients with lymphoma who were treated with combination chemotherapy containing Vinca alkaloids (vincristine and vinblastine). The patients received a total dose of 12 mg of vincristine in the case of non-Hodgkin's lymphoma and a total dose of 16 mg of vincristine in the case of Hodgkin's disease. Moreover, the patients with Hodgkin's disease received a mean total dose of 84 mg of vinblastine. Subcutaneous injections of 2 mg of Org 2766 or placebo were administered to patients with non-Hodgkin's lymphoma on days 1 and 10 of each chemotherapy course and to patients with Hodgkin's disease on days 1 and 8 of each chemotherapy course. The first injection was always given before the administration of vincristine. Assessment of neurologic symptoms and signs and measurement of sensory thresholds (vibration sense and temperature sense) were performed on day 1 of the first, fourth, and sixth (or eighth) courses and 6 weeks after cessation of chemotherapy. Thirteen patients (mean age, 44.7 years) received Org 2766 and 15 patients (mean age, 54.7 years) received placebo. More symptoms occurred in the placebo group, but only numbness and autonomic complaints occurred significantly more often in the placebo group. Motor deficit and sensory disturbances were more severe and also occurred significantly more often in the placebo group. There was no difference with respect to reflex examination findings and sensory thresholds.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocorticotropic Hormone↗
PubMed1992

The effect of 4-aminopyridine on clinical signs in multiple sclerosis: a randomized, placebo-controlled, double-blind, cross-over study.

To find out whether treatment with 4-aminopyridine is beneficial in multiple sclerosis (MS), 70 patients with definite MS entered into a randomized, double-blind, placebo-controlled, cross-over trial in which they were treated with 4-aminopyridine and placebo for 12 weeks each (maximum dose, 0.5 mg/kg of body weight). The estimated effect of the treatment as measured with the Kurtzke expanded disability status scale, which was the main evaluation parameter, was 0.28 point (p = 0.001). A significant decrease in the scale score (1.0 point or more) was encountered in 10 patients (16.4%) during oral treatment with 4-aminopyridine whereas it was not seen during placebo treatment (p less than 0.05). A significant subjective improvement (defined as an improvement that significantly affected the activities of normal daily life) was indicated by 18 patients (29.5%) during 4-aminopyridine treatment and by 1 patient (1.6%) during placebo treatment (p less than 0.05). Significant improvements related to 4-aminopyridine occurred in a number of neurophysiological parameters. No serious side effects were encountered. However, subjective side effects such as paresthesias, dizziness, and light-headedness were frequently reported during 4-aminopyridine treatment. Analysis of subgroups revealed that there was no difference in efficacy between those patients randomized to receive 4-aminopyridine and then placebo and those randomized to receive placebo and then 4-aminopyridine or between patients with and those without subjective side effects. Especially patients with temperature-sensitive symptoms and patients characterized by having a longer duration of the disease and being in a progressive phase of the disease were likely to show clear clinical benefit.

4-Aminopyridine↗
PubMed1992

Evaluation of the visual system in multiple sclerosis: a comparative study of diagnostic tests.

In 22 patients with clinically definite multiple sclerosis (MS) who were without visual symptoms and had a visual acuity of at least 1.0 in both eyes at the time of measurement, the following tests were performed to detect subclinical lesions in the visual system: visual evoked potential (VEP), contrast sensitivity test (CS), flight of colours test (FOC), colour vision test (Ishihara plates) (CV) and the pupillary light reflex (PLR). VEP was abnormal in 81.8%, CS in 72.7%, FOC in 36.4%, CV in 31.8%, and PLR in 52.3% of the patients. VEP and CS together were most sensitive: combining these techniques subclinical lesions of the visual system were detected in 90.9% (20/22) of these asymptomatic patients.

Adult↗
PubMed1992

Increased visual impairment after exercise (Uhthoff's phenomenon) in multiple sclerosis: therapeutic possibilities.

The Uhthoff symptom, a transient impairment of visual function after exercise, is demonstrated in 2 multiple sclerosis patients. Following exercise, impairment of visual function, as documented most clearly by the testing of contrast sensitivity, was less obvious after body surface cooling and after treatment with orally administered 4-aminopyridine. It is hypothesized that both treatment modalities improve the nerve conduction safety factor and thereby prevent the occurrence of a conduction block, which is believed to be the mechanism underlying the Uhthoff symptom.

4-Aminopyridine↗